Screw thread gauge



June 7 1932. w. E; HOKE 1,852,146

' 7 SCREW THREADv GAUGE. I

Filed Aug. 15. 1929 y l2 Sheets-Sheet 2 24 vf 23, A v

. y wlLLlAM :.Honf.

Patented Jung 7, l1.932t

"UNITED 4's"lie"gras PATENn OFFICE WILLIAM E. HOKE, OF BALTIMORE,

MARYLAND, 'Assr'eNOa To marmi' 'maa-:An-4

f Loox CORPORATION, or Nrw YORK, N. Y., A CORPORATION or' DELAWARE screw Tunisian GAUGE I Application mea August 15, 1929. serial No. 386,079.

This invention relates toimprovements i screw thread gauges and. has forits principal objects'to provide "simple and eicient means for gauging screw threads having obliquel helicoidal root surfaces, to provide a gauge of the comparator type for gauging theminor diameter, or minimum root diameter of standardDardelet external screw threads; to provide an eilic'ient adjgistable comparator means for gauging Dardelet screw threads capable.

of use for'comparing all sizes of threads or a large range of sizes of threads ;,and to provide a variation indicating adjustable comparator for various standard sizes of Darde let threads and'simple master setting means forv setting the comparator for use in connection with threads` of various sizes. f

Other .objectspandadvantages ofthe inf vention will appear vfrom vthe following de# scription ofthe preferred embodiment of'the invention illustrated. in

drawings.

In the drawings; i `1 y A Fig; 11's a side elevation of the gauge with a ystandard Dardeletboltptherein, the bolt the accompanying support vbeing shown .in lvertical section ;4

g.v 2 a front elevation,-the upper part 4of the bolt support being shown in section.;

i support;.

showing'th'e bolt and parts of the Fig..3 a topplanview of the shi-f table bolt Fig. 4a .detail view on an enlarged scale,

sitioned as in Figs. 1 and 2; vand l Figa-5 and' 6- detailviews showing the ymaster .setting lblock positioned forl setting' thegauge for comparisonof threads with.

the standard 1/2 inch 'and Slg/16 inch sizes of Darde'let bolts; respectively. f l' l Theauge is aportable comparator of the dialin cat'or type has'a flat bottomed base member'IO of substantially square shape in plan view. -A 'vertical post or standard 11 of cylindrical cross, section rises from the base, being rigidlysecured at its lower end to the base adjacent the rear! edge and approximately rn'dway between the ends ofthe base, as`sho 'A vertically adjustable and horizontally disposedarmor bracket 12 extends forwardly support the4 dial indicator 13. Arm 12 has graduated on the dial 'of substantial length but of small area on its gent planes to the periphery-of conical porgaugarotion 10a of oblong form in plan in front of `axial line and direction from post 11 to. adjustably a split clamping sleeve 14 formed on itsforwardend embracing the reduced bottom portion 13a of thecasing of the dial indicator, a clamping screw 15 extendingthrough ears 16 o'n sleeve 14.- vThe arm 12 has a similar split sleeve 17 formed on `its rear end and embracing 4the post 11, a clampingV screw 18 extending through the ears 19 of said sleeve, similar to ears 16 of sleeve 14, to tightlyv clamp the arm to the post indifferent verti- 60 callyadjusted positions.

- The dial indicator'lih'as the. usual rotatably adjustable dial portion 20 preferably p face,l as shown, to indicate in l/lOOOths of an inch plus and minus variations from a standardfor which the gauge is set. Thel indicator has the ,usual rotatable indicator hand or pointer 21 actuated by the usual vertically movable spring pressed plunger 22 of the indicator.

-Plunger 22 in the present construction has its lower end portion 23 tapered to form a frusto-conical thread groove entering portion bottom root surface contact face' 24. `All tantlon 23 arev inclined at an angle of 81/2o to the axial line of the endwise reciprocable plunger 22, and the bottom contact face 24 of the plunger is al plane face perpendicular to'said axial line. A y The base 10 is lformed with a raisedporpost 11 and extending under theplunger 22 of the dial indicator, said raised portion having a plane top/face lying ina horizontal plane, i. e., aplaneperpendicularto the axis of the'plunger 2 2.l Portion 10' ismade suilicientlyT long and suiciently wide fore and aft of the lbase to slidably support an anvil' or bolt support 25 for fore and aft movement into and out of position below the plunger 22 and for substantial sidewise movement ofthe support, all in a plane perpendicular to the of reciprocation of the plunger. The work support or anvil 25 comprises a steel block, and has a plane'or fiat bottom sface for slidably seating on the plane top face of portion 10a of tle base,A andaplane top face 100 making an angleof vsix degrees with lits bottom face, said-top face of the anvil sloping yends ofthe anvil so to the other.

from one end edge of the oblong anvil block from the to v face of block or anvil 25, said ribs prefera ly extending diagonally across said anvil, asshown, at a slight angleto the that a bolt or other externally threadedpart seated on the tops of the lribs may extend ydirectly lengthwise"of the anvil. i i The standard Dardelet external screw thread has a root surface making an angle of six degrees with the axial lie ofthe thread, and the side walls ofthe thread groove each slope at an angle of fourteen and -one-halfV degrees to a perpendicular to the axialline of the thread. A standard Dardelet bolt is s hown in Figs. 1, 3 and 4, Jthe particular bolt shown having nine threads to the inch.

- The ribs have top plane faces 28 and 29. for contacting the oblique helicoidal root surfaces of Dardelet threads, said plane faces each being inclined at an ,angle of twelve de grees'to t e bottom face of the anvil andar- `ranged to support thefbolt at two lengthwise spaced points on the bolt vwith the axial line of the bolt and thread at an angle of six degrees to the horizontal. Faces 28 and 29 are madenarrow so that they may seat on the root surface of threads of all, or a large range of, sizes of bolts, and the side faces of the ribs are. inclined `1 to the perpendicular at an les llili to permit such seating.y` Side face 31 o rib 26 and side face 32 ofrib 27 face toward the groove, irrespective of the size of thread, but

"thread groove,

preferably said distance ismade a few' thousandths of an inch less than one inch sotl'i'at vonly the face 32 will contactsaid wall ofthe may thus still {boltsor parts havingallor a large number of sizes of threads, while facilitating fitting of 'the threadedpart'upon the lowingthe threaded part lto'gravitate ends wise-toinsure seating of rib 27 in the deepest part ofthe thread groovefylf desired, ,for

` greater precision in gauging,

rib 2.7 may be slightlyl chamfered, as shown vface 32 abuttingthe side wall of the thread eve and face ac e ofthe thread inthe 'event of lthere being a burr or rounding in the low 'corner of' the groove. The distance between A pair of ribs 26 and 27 rise `vminor diameters of threads.

points on the deepest anvil 25, and t e planes`offaces are so spaced that when said faces v38 and 39 precisely one inch as shown. The anvil blockf be used to support 'dierentf anvil and al-v at 35, to insure 29 seating -on the root sur--4 the planes of faces 33 and 34 of the two ribs is'also preferably slightly lessv than one inch, as shown.

A master gauge setting block l36 'of novel construction is shown in Eigs.' 5 and f6 for settin the gauge to read 0 when bolts with threas of a standard minor .diameter are' gauged, said master being adapted for use different standard The master of suitable metal, such as in setting' the gauge for blockI is formed steel, and has a flat or plane topl face .37 while l its bottom surfaceis divided transversely of -the block into two flat or plane faces 38 and 39 lying in parallel inclined lanes making an angle of twelve degrees Wit the plane top face 37, the faces 38 and- 39 being joined by a short intermediate planeface 4Q preferablyI making an angle of twenty and one-half degrees with a perpendicular to to face 37.

One side face of the setting] lock is proextending. to the adjacent and with associated indices of the corresponding sizes of bolts or major thread diameters, Each such measurement through the block perpendicular to face 37 conforms with a core measurement for adifferent size of bolt taken in a lineat an'an le of six de rees with?. a perpendicular to t e bolt axis etween two groove located 180 degreesv apart.

edge of 'the thread Tlie lower edges of the'- top faces.' off-the anvil ribs 26 and 27 touch 'a plane making an angle of six de ees with the flat base of the 38. and 39 are seated on lthe top faces of yribs 26 and 27,

respectively ,the topface of the master block will lie in a plane parallel with the bottom,

face ofthe anvil.

Toset thel auge for testin threads for one-half inch ol'ts, for exaiiip e, the master is applied to the anvil or bolt support, as

shown in'Fig. 5, and the anvil with the master thereon is slid on the fiat top ofraised portion l0a of the gauge base until rib 27 is positioned below-.the dial indicator plunger 22whichplungerv is sea don face 37 of the master with the plunger raised to a point .intermediate its upper and lower'limits of movement, the dial indicator being raised jor lowered by means of the adjustable support- L ingbracket 12, ifjnecessaryA for obtaining such a positioning o f the plunger.' f' The adjustable `dial of the indicator 'is Vthen rotated, if necessary,'until hand 21 points to 0 on the dial. Tche` anvil and master are then -slidout from lunder the plunger and the gauge is ready for comparing or gauging the threads' of bolts or other externally threaded members to determine jwli'ether saidthreads'have the stand- 1/1000ths of an inch the extent of over or ard minor diameter and toI indicate in' vided with graduations, preferably stamped or etched therein,

edge of face 39 and preferably also to face 37 v Y, along lines perpendicular to face 37,asshown,

, under size,`if such there be. fmaster is shownfshifted e'ndwise for settingv may be `accurately In Fig; the

the gauge for a, 49/16 inch bolt. Preferably, rib 27 on the anvilis formed'with a vertical graduation groove 41, as shown, at one end of the rib forkcoaction with the graduations on the master block to facilitate accurate setting of the gauge.- It will be understood that additional masters varying in size may be provided for sizes of indiated on the master shown.

l groove which extends along the deeper edge of the groove. `The root surface in two turns of the groove 1ocated one inch apart will seat on rib faces 28 and 29 from edge to ed e of said faces at the under side of the bolt, t e axial linerofthe bolt will make an ngle of anvil or bolt support with the bolt thus positionedis then slid under the plunger to posif root surface at a point lopposed to the point of contact of rib face 29 with the root surface. If the thread has the proper minor diameter, the hand 21 will point .to 0 on the dial, but if it has a lesser or a greater minor diameter, the hand will swing to the left lor right o-ne point on the dial foreach one-thousandth o f under or over size, respectively'.

By the peculiar arrangement of three-point contact, threads of various sizes having an oblique helicoidal rootsurface, and particularly standard Dardelet external threads, and quickly gauged as to minor diameter. It will be observed that the accuracy of the gauging isnotI dependent upon the Vend of the movable plunger contacting any particular Widthwise portion of the thread groove, since the gauging isdone in a transverse plane through the bolt at an angle to the perpendicular tothe bolt axis equal to the angle of slope of the root'surface to the bolt axis, the bolt being supported with its axisat a similar angle to the horizontal. The cocked supporting of the boltalso facilitatesor ensures seating of one kof the two opposed gauging Aroot conducting elements in A the deepest part of the. groove.

What I claim is: 1 1. In a gauge :for screw threads with 'an threads other than those bottom, said ribs being imately one inch',- and eachhaving a side face Voblique helicoidal root surface, ithe combination of a base having a l'lat to l surface portlon, meansmounted on the y.

ase for supportinga dial indicator, a dial indicator carried by said supportingme'ans having an actuating member with a single thread groove entering portion having a sln'gle thread root contacting'e'nd located above and movable up and down relatively to said iat horizontally disposed top surface portion of the base, and a support for a threaded member to be gauged freely slidable' on said flat top' surface and the axial line of its thread inclidtothe A' so horizontal at an angle equal to the angle of i helicoidalroot surface to I bs' A the plane of the bottom of the block and differentially spaced from said *blockI bottom y to sustain a Dardelet bolt with its axis atan versely thereof at an angleof 12 degrees to 'i the plane of the bottom ferentially spaced from said block bottom to sustain a Dardelet bolt' with its axis at an angle of l2'degrees'tothe plane of the block spaced apart approx# at its higher side makinglan angleof 201/2 of the block and dif- J degrees with the perpendicular to thev'block bottom and anopposite side-face making an angle of 81/2 degrees Withnsa'id lar.

4. A l provided with external .Dardelet threads,

gauge for vDardelet bolts and other' f' embers comprising supporting means for engaging the threaduroot surface at one side of the. threaded member at two'points spaced approximately one inch apart, and `an opposedmvovable means for engaging the thread root surface at the opposite side of the member and movable"transversely of a threaded member' engaged by said Jfirst-mentioned means, sald first-mentioned means having diameter along a path f grooveentering ribseach havingaplane top cator.

nl; pf/'two surface engaging plane faces lying.

in parallel planes which make an angle of twelve degrees with a perpendicular` to the path of movementof said opposed movable 5 means and are so spaced apart as to support face, said faces being arranged in parallel planes for simultaneously contacting the root 'surface of a Dardeletthread throughout their l 20 width, and means supporting the dial indi-` cator ,and anvil with said rib top faces in planes making an angle of twelve degrees with a perpendicular to the path of movement of the actuating element ofthe indi- 6. A minordiameter gauge for external Dardelet screw threads, comprising a support, a member movable horizontally on said for external `maarre' ing a thread root'surface engaging end face i* making widthwise thereofnamggle of 12 vdegrees with a perpendicular to the axilline oftheplunger and having two side faces converging toward the opposite edges of said end face at angles respectively 'of"2O1/2 and 8% degrees to the axial line of the plunger.

8. Aminor diameter gaugefor external Dardelet 'screw threadsas claimed in claim 7 wherein saidmember is slidably mounted on said supportfor -movement in a plane perpendicular to the-axial line of the plunger.

9. A minor diameter gauge for external Dardelet screw threads comprising a support, a dial indicator mounted on the support havingaispringprojected reciprocable actuating plunger formed witha thread groove entering outer end portion' tapering toward its end at. anangle of 8% degrees to the axial line of the plunger, and a member mounted on the support to slide in a plane perpendicular to the axial line of the plunger in to and out of a position opposite the outer end of the plunger, said member having a pair. of parallel thread groove'entering ribs at the face thereof which is opposed to the plunger',

said ribs each having side faces converging towards the top of the rib at .angles to the/f/Qi support and having a pair'of parallel thread axial line of the plunger-"ofQl/g groove entering elements for supporting. a degrees and a thread root engaging top face threaded member for gauging, each ofl said -making an' angle of '12 degrees with a perelements having .a plane top face and two pendicular to th'e axial line of the plunger,'

' plane side faces converging toward said top the rib top faces lying in parallel planes face, the top faces of said elements making an spaced for seating of both said faces from 3ftl 'angle of' twelve degrees with. Vthe horizontal V edge to edge on the root surface of a Dardelet and relatively arranged in parallel planes to thread engaged with said-ribs, and the side simultaneously 'engage from edge to edge faces of the two ribs 'making said. Q01/Jdethereof with the root surface of a Dardelet greje angle both facing in the same directionl thread laid thereon, the two plane side faces and eachI making an angle of 98% .degrees of ea'chelement making angles of 20% and with the top 'face ofthe rib. 105 81/2 degreesV respectively with the. 'vertical In testimonylhereolhereuntoaixamyrw and the side face making'thesnlltgleiglture.' v

extendin Vdownward from the (lowest edge of E. HOKE. the top Face of the element, and a; am indicator.having a movable actuating element provided with a thread groove entering end portion 'and mounted on the support for movement-ofsaid end portion vertically and formovement of said member horizontally below saidv end portion. Y 7. In a minor diameter gauge for external Dardelet screw-threads, the combination of a support,- agdjalindicatormounted on said 'su port having a spring projected reciproca lea-actuating plunger provided with a i thread; ooveente'ring outer c onoidal end. l portion. aving a thread root surface engaging'enditoward which said-end portion tapers Y at-'an angle of 8% degrees to the axialline of vthe-plunger",

amemberhavinga 'thread groove entering portion'and mounted on .the- .support for calipering ofa thread root between its thread oove entering-portion and 1 that of said-actuating plungerl the thread 15 groove entering portlonof s a1d member hav-l 

